Q:

What is the area of a rectangle with vertices at ​ (−6, 3) ​, ​ (−3, 6) ​ , (1, 2) , and (−2, −1) ?Enter your answer in the box. Do not round any side lengths.What is the area of a triangle with vertices at (0, −2) , ​ (8, −2) ​ , and ​ (9, 1) ​ ?Enter your answer in the box.What is the perimeter of a polygon with vertices at (−2, 1) , ​ (−2, 4) ​, (2, 7) , ​ (6, 4) ​, and (6, 1) ​?Enter your answer in the box. Do not round any side lengths.​What is the perimeter of the rectangle shown on the coordinate plane, to the nearest tenth of a unit?15.3 units20.4 units30.6 units52.0 units

Accepted Solution

A:
(1) the area of a rectangle with vertices at ​ (−6, 3) ​, ​ (−3, 6) ​ , (1, 2) , and (−2, −1) To find area of rectangle we need to find the length and widthLength = distance between (−6, 3)  and (−2, −1) Distance = [tex]\sqrt{(x_2-x_1)^2 + (y_2-y_1)^2}[/tex]=  [tex]\sqrt{(-2-(-6))^2 + (-1-3)^2}[/tex]=  [tex]\sqrt{(4)^2 + (-4)^2}[/tex]=[tex]\sqrt{(16) + 16}[/tex] =[tex]\sqrt{32}[/tex]width = Distance between (−6, 3) ​, ​ (−3, 6)Distance = [tex]\sqrt{(-3-(-6))^2 + (6-3)^2}[/tex]=[tex]\sqrt{3^2+3^2}= \sqrt{18}[/tex]Area = Length * width = [tex]\sqrt{32} *\sqrt{18} = \sqrt{576}= 24[/tex](2)  the area of a triangle with vertices at (0, −2) , ​ (8, −2) ​ , and ​ (9, 1) ​ Area of triangle = [tex]\frac{1}{2} * base * height[/tex]base  is the distance between (0,-2) and (8,-2) Distance =  [tex]\sqrt{(8-0)^2 + (-2-(-2))^2}[/tex] = 8To find out height we take two vertices (8,-2) and (9,1)Height is the change in y values = 1- (-2) = 3base = 8  and height = 3So area of triangle = [tex]\frac{1}{2} * 8 * 3 = 12[/tex](3) the perimeter of a polygon with vertices at (−2, 1) , ​ (−2, 4) ​, (2, 7) , ​ (6, 4) ​, and (6, 1) ​To find perimeter we add  the length of all the sidesDistance between (−2, 1)  and (−2, 4) = [tex]\sqrt{(-2+2)^2 + (4-1)^2}[/tex]= 3Distance between(−2, 4) ​and (2, 7) = [tex]\sqrt{(2+2)^2 + (7-4)^2}[/tex]= 5Distance between (2, 7)  and (6, 4) = [tex]\sqrt{(6 - 2)^2 + (4-7)^2}[/tex]= 5Distance between (6, 4) ​ and (6, 1) ​= [tex]\sqrt{(6 - 6)^2 + (1-4)^2}[/tex]= 3Distance between  (6, 1) and (−2, 1) ​= [tex]\sqrt{(-2-6)^2 + (1-1)^2}[/tex]= 8Perimeter = 3 + 5 + 5 + 3 + 8 = 24 (4) four coordinates are (-7,-1) (-6,4) (3,-3) and (4,2)Length = Distance between  (3,-3) and (4,2) ​= [tex]\sqrt{(4-3)^2 + (2+3)^2}[/tex]= [tex]\sqrt{26}[/tex]Width = Distance between (-6,4) and (4,2) ​= [tex]\sqrt{(4+6)^2 + (2-4)^2}[/tex]= [tex]\sqrt{104}[/tex]Perimeter = 2(lenght + width) = 2*( [tex]\sqrt{26}[/tex]+[tex]\sqrt{104}[/tex] )= 30.6 units